Researchers at the University of California Riverside and elsewhere have just published a paper linking the effects of climate change to more frequent and intense flooding. It has to do with the effects of temperature, rainfall, and humidity on the macropores in the soil—that is, the spaces larger than 0.08 millimeters, which, when they’re plentiful, allow water to infiltrate easily.

The research team used a soils database containing 50 years of information from throughout the US as well as historical atmospheric data from weather stations. Comparing macroporosity to rainfall, temperature, and humidity, they found that, as expected, macropores develop more easily in dry conditions than humid ones, and that changes in macroporosity occur relatively quickly.

Climate models indicate that humidity will increase throughout most of the continental US by 2100, which means fewer and smaller macropores. This, in turn, will likely mean less infiltration, less transport of nutrients to plant roots, slower aquifer replenishment, and greater surface runoff, erosion, and flash-flooding.

“It is important to predict the response of macroporosity to climate change because of its role in the water cycle, and ultimately in water scarcity, food security, human health and loss of biodiversity,” says the study’s lead author, Daniel Hirmas, an associate professor in the Department of Environmental Sciences at UC Riverside. The authors are recommending that macroporosity be added to global climate models.

The paper, titled “Climate-Induced Changes in Continental-Scale Soil Macroporosity May Intensify Water Cycle,” was published in the journal Nature. The work was funded by the USDA’s Agriculture and Food Research Initiative and by the Norwegian Institute of Bioeconomy Research.